1. Field of the Invention
The present invention relates to a lighting apparatus using microwaves and in particular to a lighting apparatus using microwaves which is capable of emitting lights by applying microwaves an electrodeless bulb.
2. Description of the Conventional Art
A lighting apparatus using microwaves emits visible rays or ultraviolet rays by applying microwaves to an electrodeless bulb, it has longer life span and better lighting effectiveness than a general incandescent lamp or a fluorescent lamp.
FIG. 1 is a longitudinal sectional view illustrating an internal structure of a lighting apparatus using microwaves.
A lighting apparatus using microwaves includes a magnetron 1, a waveguide 3 transmitting microwaves from the magnetron 1 to a bulb 5, the bulb 5 emitting light from the plasma generated from the enclosed materials which are excited by the microwave energy transmitted through the waveguide 3, and a resonator 10 placed in front of the waveguide 3 and the bulb 5, excluding the microwaves and transmitting the light emitted from the bulb 5.
Particularly, the resonator 10 has a cylindrical shape and has a metal mesh structure in order to exclude microwaves while transmitting the light emitted from the bulb 5.
The lighting apparatus using microwaves further includes a high voltage generator 7 for boosting the voltage of an alternating current and supplying it to the magnetron 1, a cooling unit 9 for refrigerating the magnetron 1 and the high voltage generator 7, a reflector 11 intensively reflecting the light emitted from the bulb 5, and a control unit (not shown) controlling various elements including the high voltage generator 7 and the cooling unit 9.
In the lighting apparatus using microwaves, when an operating signal is inputted from the control unit to the high voltage generator 7, the high voltage generator 7 boost the voltage of the AC power and supplies the boosted AC power to the magnetron 1.
The magnetron 1 oscillates due to the high voltage supplied from the high voltage generator 7 and generates microwaves having a very high frequency, the generated microwaves are emitted into the resonator 10 through the waveguide 3, materials enclosed inside the bulb 5 are discharged, accordingly light having an inherent emission spectrum is generated.
The light generated from the bulb 5 is reflected by a mirror 12 and the reflector 11 and lights up a space.
However, in the lighting apparatus using microwaves in accordance with the background art, because the resonator 10 is constructed with a cylindrical metal mesh, most of the light emitted from the bulb 5 transmits through the metal mesh, and part of the light is reflected on the metal mesh and scattered all over the place inside the resonator 10, accordingly there is a limitation in maximizing a lighting efficiency.
In more detail, because the resonator 10 has the cylindrical shape, a focus of the light reflected onto the metal mesh is not fixed and the light is reflected intricately and scattered all over the place, accordingly the lighting efficiency is lowered due to the loss of the light.
In addition, because the resonator 10 projects lengthwise from the front of the waveguide 3, and a large size reflector 11 is required to surround the resonator 10, it is difficult to minimize the size of the lighting system.
In order to solve the above-mentioned problems, it is an object of the present invention to provide a lighting apparatus using microwaves which is capable of improving a lighting efficiency and miniaturizing a lighting system by minimizing a loss of light emitted from a bulb by installing a waveguide inside a resonator and installing a bulb at the center of the resonator.
In order to achieve the object of the present invention, a lighting apparatus using microwaves includes a resonator transmitting a light but preventing the escape of microwaves, a waveguide placed at an internal domain of the resonator and transmuting the microwaves, a microwave generating means installed at the side of the resonator and transmitting microwaves into the waveguide, and a bulb placed at the center of the resonator and emitting light resulting from a plasma which is excited by the microwaves transmitted through the waveguide.
Herein, the resonator has a spherical shape, and the waveguide is installed within a radial sector of the resonator.
The waveguide has a conical shape, the vertex of the waveguide is placed at the center of the resonator, the cover portion of the waveguide is formed as a curved surface having a shape the same as the spherical shape of the resonator and Is placed so as to correspond to an external extended portion of the resonator.
The lighting apparatus using microwaves having the microwave generating means further includes a high voltage generator and a casing covering a cooling unit, and the casing is combined and fixed to the cover portion of the waveguide at the external extended portion of the resonator.
The bulb is placed at the center of the resonator, and the microwave generating means is fixed to the waveguide at the external extended portion of the resonator.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.